1. Field of the Invention
The present invention relates to a dynamic speaker, particularly to a structure of fixing a lead wire of a voice coil.
2. Description of the Related Art
A dynamic speaker is conventionally known among the types of a speaker. As shown JP-A-6-178390, a dynamic speaker comprises a diaphragm having a voice coil attached on the lower surface, and a frame disposed on the lower side of the diaphragm and adapted to support the diaphragm at the periphery thereof. A pair of lead wires drawn from the voice coil is fixed to a pair of terminal members mounted on the lower side of the frame by soldering or other means.
The manufacturing process of the conventional dynamic speaker is described. The voice coil is attached to the diaphragm, the diaphragm is bonded to the frame with the lead wires drawn outside the diaphragm and the frame, the assembly of the diaphragm, the voice coil and the frame is turned upside down, and the leading ends of the lead wires are fixed to the terminal members.
Conventionally, the manufacturing process is complicated since the assembly of the diaphragm, the voice coil and the frame needs to be turned. upside down.
Further, when the assembly is turned upside down, the leading ends of the lead wires are free, therefore, there is a risk of a breakage of wire.
Further, after the lead wire is fixed to the terminal member, part of the lead wire is exposed outside the frame so that the operator may touch the wire, possibly also causing a breakage of wire. The conventional speaker therefore requires a protection against such unintentional breakage.
An object of the present invention is to provide a speaker which simplifies the manufacturing process and prevents a breakage of the lead wire.
The speaker of the present invention achieves the object by providing a land portion of the terminal member on the upper side of the frame.
A speaker of the present invention comprises:
a diaphragm;
a voice coil attached to the lower surface of the diaphragm;
a frame disposed on the lower side of the diaphragm and supporting the diaphragm at the outer edge thereof and
a pair of terminal member mounted on the frame and having a portion where a pair of lead wire drawn from the voice coil is fixed;
wherein the portion is disposed on the upper side of the frame.
The words such as xe2x80x9clowerxe2x80x9d and xe2x80x9cupperxe2x80x9d are used for the purpose of explanation to clarify the positional relationship of the members. The actual direction or orientation of the speaker when operated is not thereby limited.
Any type of xe2x80x9cdiaphragmxe2x80x9d and xe2x80x9cvoice coilxe2x80x9d may be used as far as applicable as an element of a dynamic speaker.
Any type of xe2x80x9cterminal memberxe2x80x9d may be used as far as the portion is made of conductive material and disposed on the upper side of the frame.
The lead wire is fixed to the portion of the terminal member for electrical connection. Any type of fixing method is applicable such as soldering and thermo-compression bonding.
According to the speaker of the present invention, the frame is disposed on the lower side of the diaphragm, the diaphragm is supported by the frame at the periphery, the pair of terminal member is mounted on the frame, and a pair of lead wire drawn from the voice coil is fixed and electrically connected to the land portion of the terminal member. Since the land portion of the terminal member is disposed on the upper side of the frame, fixation of the lead wire can be performed without turning the frame upside down.
This simplifies the manufacturing process of the speaker and also prevents a breakage of the lead wire that conventionally happens when the frame is turned upside down. Further, this prevents the operator from unintentionally touching the lead wire since no part of the lead wire is exposed outside the frame after the fixation.
According to this invention, the manufacturing process is simplified and a breakage of wire is prevented.
The land portion may be plate-shaped and provided along the upper side of the frame. The lead wire may be fixed to the land portion by thermo-compression bonding method. This eliminates a conventional soldering process and contributes to an environmental lead-free structure. This effectively reduces a space for fixation since a space for solder spot is not required. Continuity failure is also considerably lessened since this method provides more reliable continuity.
The xe2x80x9cthermo-compression bondingxe2x80x9d is a method applying heat and pressing force. Any type of heating method may be used as far as it melts the insulation coating of the lead wire so that the exposed core of the wire may be pressed against the land portion of the terminal member by pressing force. For example, the following three methods are applicable: 1) supplying current between the lead wires; 2) supplying current between the terminal member and a thermo-compression bonding jig holding the lead wire; and 3) pre-heating the jig and pressing the heated jig against the lead wire.
The placement of the land portion is not limited as far as it is located on the upper side of the frame. The land portion is preferably disposed inside the outer edge of the diaphragm. In this case, the diaphragm provides protection for the lead wire fixed on the land portion. Further, the external shape of the speaker may be designed to that of the diaphragm so as to obtain a compact sized speaker.
Any material may be used for the xe2x80x9cframexe2x80x9d. If the frame is made of insulating material, the terminal member may be directly mounted on the frame without applying an insulating coating on the surface of the frame.
The frame may be molded of synthetic resin and the terminal member may be integrally formed with the frame by insert molding. This improves the mounting strength of the terminal member, and enables part of the terminal member to be easily protruded outside the speaker.
The upper surface of the land portion may be placed lower than the upper end of the voice coil. Then, the lead wire may be traveled enough away from the diaphragm. This prevents the lead wire from interfering with the diaphragm during an operation of the speaker, thereby preventing an occurrence of abnormal sound. A breakage of wire due to the interference is also prevented and therefore the durability of the speaker is improved. Degree of freedom in designing the diaphragm, especially the cross-sectional shape thereof, is also enhanced.
The difference in height between the upper surface of the land portion and the upper end of the voice coil may be varied to the size of the speaker and the cross-sectional shape of the diaphragm. Preferably, the difference is 0.1 mm or more. More preferably, it is 0.2 mm or more.